The bulb in my newly acquired Tremoverb just burned out so I went to Radioshack and bought a couple new ones and a new problem arose. I can't seem to get the bulb in there. I push it in as far back as it will go against the spring but it won't turn to the right to lock it in place no matter what I try or how many times. Is there some kind of trick to this? It wouldn't seem like something so simple should be such a difficult task.